Method and apparatus for identifying the type of optical recording medium

Abstract

A method and an apparatus for identifying the type of an optical recording medium are provided. The method includes detecting a surface reflected signal S S and a writable-surface reflected signal S R of an optical recording medium while performing a focus search using a first optical system, counting a time difference DT S between a high peak and a low peak of the surface reflected signal S S , counting a time difference DT R between the high peak of the surface reflected signal and a high peak of the writable-surface reflected signal S R , obtaining DT by substituting DT R and DT S into the following equation: DT = ( DT R ) a ( DT S ) b ⁢ ⁢ ( a - b ≥ 1 2 ) and comparing DT with a reference time T, and driving the first optical system if DT is greater than T and driving a second optical system if DT is not greater than T.

1. A method identifying the type of an optical recording medium, comprising:
 detecting a surface reflected signal S S  and a writable-surface reflected signal S R  of an optical recording medium while performing a focus search using a first optical system; 
 counting a time difference DT S  between a high peak and a low peak of the surface reflected signal S S ; 
 counting a time difference DT R  between the high peak of the surface reflected signal and a high peak of the writable-surface reflected signal S R ; 
 obtaining DT by substituting DT R  and DT S  into the following equation: 
 
     
       
         
           
             DT 
             = 
             
               ( 
               
                 
                   
                     ( 
                     
                       DT 
                       R 
                     
                     ) 
                   
                   a 
                 
                 / 
                 
                   
                     ( 
                     
                       DT 
                       S 
                     
                     ) 
                   
                   b 
                 
               
               ) 
             
           
         
       
     
     where (a−b≧½) and comparing DT with a reference time T; and
 driving the first optical system if DT is greater than T and driving a second optical system if DT is not greater than T. 
 
   
   
     2. The method of  claim 1 , wherein DT R  of the first optical system is greater than DT R  of the second optical system. 
   
   
     3. The method of  claim 2 , wherein the first optical system is a CD optical system. 
   
   
     4. The method of  claim 3 , wherein the second optical system is a DVD optical system. 
   
   
     5. The method of  claim 1 , further comprising:
 activating a laser diode of the first optical system; and 
 performing the focus search with the laser diode of the first optical system. 
 
   
   
     6. An apparatus identifying the type of an optical recording medium, comprising:
 a signal detector which detects a surface reflected signal S S  and a writable-surface reflected signal S R  of an optical recording medium while performing a focus search using a first optical system when the optical recording medium is inserted; 
 a calculator which counts a time difference DT S  between a high peak and a low peak of the surface reflected signal S S  and a time difference DT R  between the high peak of the surface reflected signal and a high peak of the writable-surface reflected signal S R , and obtains DT by substituting DT R  and DT S  into the following equation: 
 
     
       
         
           
             DT 
             = 
             
               ( 
               
                 
                   
                     ( 
                     
                       DT 
                       R 
                     
                     ) 
                   
                   a 
                 
                 / 
                 
                   
                     ( 
                     
                       DT 
                       S 
                     
                     ) 
                   
                   b 
                 
               
               ) 
             
           
         
       
     
     where (a−b≧½); and
 an optical recording medium identification unit which identifies the type of the optical recording medium by comparing DT with a reference time T stored in advance and outputs a signal used to drive a first optical system or a second optical system. 
 
   
   
     7. The apparatus of  claim 6 , wherein DT R  of the first optical system is greater than DT R  of the second optical system. 
   
   
     8. The apparatus of  claim 7 , wherein the optical recording medium identification unit drives the first optical system if DT is greater than T and drives the second optical system if DT is not greater than T. 
   
   
     9. The apparatus of  claim 8 , wherein the first optical system is a CD optical system. 
   
   
     10. The apparatus of  claim 9 , wherein the second optical system is a DVD optical system. 
   
   
     11. A method of selecting an optical media system compatible with an optical recording medium type, the method comprising:
 counting a time difference DT S  between a high peak and a low peak of a surface reflected signal S S  and a time difference DT R  between the high peak of the surface reflected signal and a high peak of a writable-surface reflected signal S R ; 
 driving a first optical system if DT is greater than a reference time T and driving a second optical system if DT is not greater than T, 
 wherein DT is calculated as
     DT =(( DT   R ) a /( DT   S ) b ) where ( a−b≧ ½). 
 
 
   
   
     12. An optical system that records/reproduces data on/from an optical recording medium having a first optical format type or a second optical format type, comprising:
 an optical pickup that transmits light beams onto an optical recording medium; 
 a focus servo controller that identifies the optical recording format type as either the first optical format type or the second optical format type by comparing DT with a reference time T, wherein DT is calculated by counting a time difference DT S  between a high peak and a low peak of a surface reflected signal S S  of the light beam and a time difference DT R  between the high peak of the surface reflected signal and a high peak of a writable-surface reflected signal S R , of the light beam and substituting DT R  and DT S  into the equation:
     DT =(( DT   R ) a /( DT   S ) b ) where ( a−b≧ ½). 
 
 
   
   
     13. The optical system of  claim 12 , wherein the focus servo controller comprises:
 a signal detector that detects the surface reflected signal S S  and the writable-surface reflected signal S R . 
 
   
   
     14. The optical system of  claim 12 , wherein the focus servo controller comprises:
 a calculator that counts the time difference DT S  and the time difference DT R . 
 
   
   
     15. The optical system of  claim 12 , wherein the focus servo controller comprises:
 an optical recording identification unit that identifies the optical recording medium as having the first optical format type if DT is less than the reference time T or as having the second optical format type if DT is greater than the reference time T. 
 
   
   
     16. The optical system of  claim 15 , wherein the optical recording identification unit outputs a first signal used to drive a first optical system compatible with the first optical format type or a second signal used to drive a second optical system compatible with the second optical format type. 
   
   
     17. The system of  claim 12 , further comprising:
 an encoder that encodes data to be recorded on the optical recording medium into write pulses having the first optical format type or the second optical format type. 
 
   
   
     18. The system of  claim 12 , further comprising:
 a decoder that retrieves original data from the optical recording medium. 
 
   
   
     19. The system of  claim 12 , further comprising:
 a microcomputer that receives recording commands from a host for forwarding to the focus servo controller. 
 
   
   
     20. The system of  claim 19 , further comprising:
 an interface that converts decoded data from the optical system into packet-type protocol data to be processed by the host. 
 
   
   
     21. The system of  claim 12 , further comprising:
 a focus servo driver that follows tracks of the optical recording medium by moving the optical pickup in a direction perpendicular to the optical recording medium while driving a focus actuator in the optical pickup. 
 
   
   
     22. The system of  claim 12 , further comprising:
 a tracking servo driver that adjusts the location of the light beam and follows tracks of the optical recording medium by moving an object lens of the optical pickup in a radial direction while driving a tracking actuator in the optical pickup. 
 
   
   
     23. The system of  claim 12 , further comprising:
 a disk motor rotating the optical recording medium at a predetermined speed according to the first optical format type or the second optical format type.